Since players have no motivation to go to dungeons anymore, add a map with super high rewards (Insane Maps, Dual 5 Items, Legends, Raja Emblems) but the risk is, if you die, you lose everything on you at that time.

Obviously, you wouldn't go there with your full legend sets, unless you think you're not going to die. You would take a much cheaper set (Dual 1 LGs for example)